Box extrusion



FIG. 1 is a perspective view of a box extrusion showing my new design;

FIG. 2 is a right end elevational view thereof, the left end elevational view being a mirror image thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a box extrusion, as shown and described. 